iostream vs. stdio

so, I've got EXPERT PROGRAMMERS telling me to use printf instead of cout in c++, ok but why? what is the difference (in b4 stream)

I was just thinking about iostreams yesterday. What the fuck? Why did they ever think
cout << "Yo" << " I'm " << 6 " fags!" << endl;
was a good idea? Not only does it look like bit shifts, it's longer and harder to read than the alternative would have been.